Abstract

A high yielding method for the aqueous exfoliation of graphite crystals to produce high quality graphene nanosheets in a kitchen blender is described here. Bovine serum albumin (BSA), beta-lactoglobulin, ovalbumin, lysozyme, and hemoglobin as well as calf serum were used for the exfoliation of graphene. Among these, BSA gave the maximum exfoliation efficiency, exceeding 4 mg mL(-1) h(-1) of graphene. Quality of graphene produced was examined by Raman spectroscopy, which indicated 3 5 layer graphene of very high quality and very low levels of defects. Transmission electron microscopy indicated an average size of similar to 0.5 mu m flakes. The graphene/BSA dispersions were stable over pH 3.0-11, and at 5 degrees C or 50 degrees C, for more than 2 months. Current approach gave higher rates of BSA/graphene (BioGraphene) in better yields than other methods. Calf serum, when used in place of BSA, also gave high yields of good quality BioGraphene and these preparations may be of direct use for cell culture studies. A simple example of BioGraphene preparation is described that can be adapted in most laboratories, and graphene-adsorbed glucose oxidase is nearly as active as the free enzyme. Current approach may facilitate large-scale production of graphene in most laboratories around the world and it may open new opportunities for biological applications of graphene.